DEVELOPMENT OF A BIOSENSOR SYSTEM FOR EVA LUATION OF GOOD WATER FOR SAKE BREWING

A Bow-type biosensor able to detect minerals in water was constructed on a trial basis using immobilized yeast cells and a semiconductor eth anol sensor. This biosensor detected minerals within 20-30 min and rem ained relatively stable for about one month. The sensor output, expres sed as delta volts (Delta V), which is the difference between the amou nt of ethanol formed with deionized water and that formed with the tes t water, was correlated with the total hardness of the waters tested. Many kinds of water, such as well waters from sake factories, and vari ous spring and well waters marketed in the Hiroshima district for thei r palatable qualities, were analyzed using the biosensor. The outputs showed that the ethanol fermentation abilities of waters from sake fac tories (0.18-0.35 Delta V) were higher than those of bottled waters (0 .02-0.2 Delta V). It is thought that the sensor might be suitable for the rapid and convenient detection of potential ethanol production abi lity in water.